Electric drive for a vehicle

ABSTRACT

Electric drive for a vehicle includes a housing that is stationary in relation to a vehicle chassis or frame. A motor housing is arranged in the housing. A stator and a rotor are arranged in the motor housing. The rotor and the stator are rotatably mounted. The motor housing and the rotor are capable of rotating in opposite directions. A first drive train is connected to one of the rotor and the motor housing. A first transmission device connects one of the rotor and the motor housing to the first drive train whereby the first drive train produces a first output rotation. A second drive train connects to another of the rotor and motor housing. A second transmission device connects another of the rotor and the motor housing to the second drive train whereby the second drive train produces a second output rotation. Each of the first and second transmission devices includes a planetary gear.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a National Stage Application of InternationalApplication No. PCT/AT01/00019, filed Jan. 26, 2001. Further, thepresent application claims priority under 35 U.S.C. §119 of AustrianPatent Application No. A133/00 filed on Jan. 28, 2000.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an electric drive for vehicles.

2. Discussion of Background Information

U.S. Pat. No. 516,917 A describes an electric drive that is used fordriving two wheels independently, whereby one wheel is connected to thefield winding so as to be stationary in relation to the winding, and theother wheel is connected to the rotor via a differential gear. In orderto achieve an equal torque on both wheels the differential gear must,with the field winding and rotor running at the same speed, effect areverse in the direction of rotation of the rotor only, without changingthe speed. This is the case in the embodiments shown, on the one hand asa differential gear ring similar to the arrangement in known axledifferentials, on the other hand as a spur pinion-planetary gear withthe same function.

Furthermore, U.S. Pat. No. 613,894 describes a dynamo and electric drivefor vehicles. In this embodiment with two electric components capable ofcoaxial rotation, the two components are connected to each other by agear unit with high speed reducing ratio, and to a stationary part. Inone embodiment, it is suggested that the housing of the rotating fieldwinding should be connected to a drive wheel of the vehicle so as to bestationary in relation to the wheel. In a further embodiment, theinternal shaft is to be used as a drive for slow-running machines.

Furthermore, a device with a rotating field winding is known, wherebycurrent is supplied to the field winding via slip rings. The equallyrotating rotor drives the housing of the field winding via a planetarygear with a high speed-increasing ratio. As in U.S. Pat. No. 613,894 A,this unit is used preferably for slow-running machines, for example as adrum drive for winches, whereby the entire drive has room within thedrum.

A drive train for an electric vehicle is also described in U.S. Pat. No.5,845,732 A. Thereby, one drive shaft is connected to a rotor that isarranged coaxially with the wheel shafts, whereby the rotor is mountedon a hollow shaft and drives the sun gear of a planetary gear. The webof this gear is connected to a wheel shaft that runs through the hollowrotor shaft. The ring gear of the gear is connected to the web ofanother planetary gear that is arranged coaxially with the rotor shaft.This gear has to effect a torque reversal so that the second wheelshaft, to which it is connected, rotates in the same direction as thefirst wheel shaft. The disadvantage of this embodiment is the need for ahollow shaft to accommodate the rotor.

U.S. Pat. No. 5,487,438 and EP 0 587 120 A3 describe a drive system foran electric vehicle. Within the scope of this drive system, an axledrive is shown in which the field winding, which is mounted so as to becapable of rotation and which is supplied via slip rings, is connectedto the pinion of a gear unit. This pinion engages with a ring gear whichin turn is connected to one of the wheel shafts so as to be stationaryin relation to the shaft. In this gear unit, the pinion and the ringgear rotate in the same direction. The rotor, which is also mounted soas to be capable of rotation, drives a spur pinion that engages withanother spur pinion that is connected to the other wheel shaft. Thisgear unit effects rotation of the wheel shaft in the opposite directionin relation to rotation of the rotor. The function of a differentialgear is thus provided. With a suitable choice of gear wheel diameters,the wheel shafts can be aligned. The disadvantage of this embodiment isthe fact that the field winding and the rotor rotate around anadditional axle parallel to the wheel shafts, thus increasing the costsof construction of the housing. Furthermore, the intended highspeed-increasing ratios require a large diameter for the ring gear ofthe gear unit, which reduces the ground clearance of vehicles with suchan axle to a level that is not permissible.

U.S. Pat. No. 5,804,935 describes a drive system for electric vehicles.

This drive system is intended for vehicles with two driven axles,whereby a field winding that is mounted so as to be capable of rotationdrives one wheel axle. With suitable devices, this drive train can beinterrupted and the field winding can be fixed to the vehicle while thedrive axle runs freely. Furthermore, a rotor is provided that drives theother drive axle. The current for the rotating field winding is providedvia slip rings. The rotary movement of the rotor or field winding istransmitted directly to the connecting shaft to the drive axles. Underthe condition that the rotor has the same rpm with reference to thestator, it is possible with the help of this device, with a fixed rotorand driving only one wheel axle, to achieve twice the driving speed aswhen driving both axles. In addition to the suitability of such a drivedevice only for vehicles with two driven wheel axles, a reduction gearmust also be provided for each wheel axle in order to achieve areasonable embodiment in terms of construction.

GB 2 008 862 A describes a double rotor with friction brakes.

A device is described in which both the field winding and the rotor areindependently mounted on a joint axle so as to be capable of rotationand which can be fixed by means of friction brakes. Current istransmitted via slip rings. The rotational movement of the rotor and thefield winding are superimposed in a suitable planetary gear unit.Downstream from this unit, there is a reduction gear for drivingprimarily a winch drum. By arresting the rotor or field windings, greatdifferences in the rpm of the winch drum can be achieved, thus improvingthe handling of the relevant hoisting device or of a machine withsimilar specifications.

Furthermore, GB 2 254 965 A describes a gear system for vehicles drivenby an electric motor. A device is proposed in which both the rotor andthe field winding of a direct current unit are mounted on a mutual axleso as to be capable of rotation. Thereby, the rotor shaft is mounted onthe vehicle so as to be capable of rotation at one end, and in therotating housing of the field winding at the other end. The rotatinghousing of the field winding has a shaft stump at one end that ismounted on the vehicle. At the other end, the housing is mounted on therotor shaft. The operating current is transmitted by slip rings that aremounted on the outer diameter of the housing of the field winding. Therotor has a collector that is supplied via rotating brushes connected tothe housing.

U.S. Pat. No. 4,130,172 A describes an electric vehicle. In thisdisclosure, an electric motor drive system is described whereby therotor and the field winding are arranged on a common axle so as to beable to rotate, whereby the direction of rotation of one of the outputshafts is reversed with reference to the rotor movement by a bevel gear.The other output shaft is fixed rigidly to the rotation of the fieldwinding. Since the described embodiment does not perform a reduction inrpm of the output shafts with reference to rotor and field coil, thedrive wheels of the vehicle must be connected to the respective outputshafts by means of a belt drive.

AT 405 924 B describes an electric drive for vehicles. This disclosureshows that the opposite direction of movement of rotor and field windingcan be reduced to the wheel rpm either in the same or in oppositedirections with a suitable planetary gear device, thus fulfilling thefunction of a gear drive with differential function. With the describedgear units, rotor, field winding and wheel shafts can be arranged on oneaxis of rotation.

An axle drive for a vehicle is also known, whereby the rotor and thefield winding are mounted so as to be capable of rotation and drive onewheel each. Both the main and the excitation current are supplied to themoving motor parts via an appropriately arranged slip ring transmissiondevice. The necessary reduction to the rpm of the drive wheels isachieved with a two-step spur pinion unit for both the rotor and thefield winding. An idler gear is inserted in one of these gears, thusachieving an opposite direction of rotation of the drive and output inthis train. With a suitable choice of the spur pinions for this gearunit, it is possible to have the wheel shafts and the rotor-fieldwinding assembly on one common axle.

Furthermore, EP 0 867 324 A2 describes a vehicle, in particular a forklift truck, that can be operated by an electric motor with stator androtor rotating in opposite directions. In this disclosure, an axle drivedevice for floor conveyors is described whereby one wheel is driven bythe rotating stator via a reduction gear and the other wheel is drivenby the rotor via a spur pinion for reversal of direction as well as by afurther reduction gear. With the functional separation between rpmreversal and reduction to wheel rpm, the cost of construction for twoseparate reduction gears is necessary in addition to the reversingmechanism.

Furthermore, U.S. Pat. No. 3,267,311 A describes a combination of anelectric motor and a differential drive for a vehicle. The axle drivefor the vehicle consists of a rotating field winding that is connectedrigidly to one wheel, and a rotor rotating on the same axle that isconnected to the other wheel via a gear unit. The gear unit consists ofa spur pinion connected to the rotor, which engages with idler gears.The axes of rotation of the idlers are fixed in relation to the housingand in turn engage with a ring gear that is arranged coaxially with therotor axle. With this gear unit, a reversal of direction between rotorand wheel shaft is achieved. Since this gear also effects a speedreduction that is not negligible, the torques on the left and rightwheel are necessarily different. Therefore and because of the lowerspeed reduction between the electric motor components and the drivewheels, the suitability of this combination for motor drives isquestionable.

SUMMARY OF THE INVENTION

The aim of this invention is to provide an electric drive that avoidsthe disadvantages of the above mentioned drives on the one hand, andthat is easy to construct on the other hand.

The aim of this invention is achieved with an electric drive for avehicle, in particular for a multi-track electric motor vehicle, wherebya housing that is stationary in relation to the vehicle chassis or frameis provided and a motor housing with a stator and a rotor, which arerotationally mounted within this motor housing, is provided. The motorhousing and the rotor perform opposite rotational movements for output,whereby a drive train is connected to the rotor or to the motor housingand the rotational movement of the rotor or the motor housing is carriedout by way of a transmission device with the same drive and outputdirection of rotation. The remaining drive train is connected to themotor housing or the rotor and the rotational movement of the motorhousing or rotor is carried out by way of a transmission device withopposite drive and output direction of rotation, wherein the rotorengages with the planet wheels of the allocated planetary gear by way ofa spur pinion that is arranged on the shaft or the motor housing engageswith the planet wheels of the allocated planetary gear by way of a spurpinion that is connected to the motor housing and is arranged on theaxis of the motor housing. A web is provided that is connected to theaxles of the planet wheels of each planetary gear and drives the wheelshaft assigned thereto.

The surprising advantage resulting from the features mentioned abovemust be seen primarily in the fact that a high speed increase for anelectric motor is achieved in one gear step. According to the state ofthe art, such a high speed increase can normally be achieved only with athree-step spur pinion. Furthermore, the invention offers the benefit ofan even torque distribution between the two wheel shafts. The reversinggear, where drive and output are arranged coaxially, makes a compactconstruction of the drive possible. In such a gear, the torque istransmitted by several sets of planet wheels for each gear. With theresulting optimal branching of output, a compact construction ispossible.

A further advantage of the invention lies in the fact that by connectingthe bridge to the wheel shafts the circumference speeds of the planetarywheels are lower and thus there are lower centrifugal forces.

With this drive according to the invention, a hollow shaft through therotor with a complicated bearing mounting is not required to operate theopposite wheel shaft.

The invention also makes it possible to construct the entire gear unitto fit the diameter of the motor housing. This results in favorableassembly dimensions for production engineering, which in turn guaranteesa good or high ground clearance with reference to the vehicle design.

The invention also makes it possible to guarantee a simple constructionallowing an economic production of the entire drive system.

It is also possible to design a drive that is arranged between the leftand right drive wheel, which provides the differential function, andthereby requires so little space that a rigid coaxial connection betweenthe wheel axles and the drive is possible without reducing the groundclearance of the vehicle to a level that is not permissible.

Another significant advantage of the drive system in accordance with theinvention is the fact that when the vehicle is driving straight aheadthe rotor rpm is approximately the same as the stator rpm. As is known,the sum of the speeds is important for the output capacity. The noiselevel, on the other hand, depends on the maximum rpm occurring in thesystem. The drive system

In a further embodiment of the invention, speed increases can beachieved that can meet the required specifications optimally.

The invention also provides for an electric drive for a vehicle,comprising a housing that is stationary in relation to a vehicle chassisor frame. A motor housing is arranged in the housing. A stator and arotor are arranged in the motor housing. The rotor and the stator arerotatably mounted. The motor housing and the rotor are capable ofrotating in opposite directions. A first drive train connects to one ofthe rotor and the motor housing. A first transmission device connectsone of the rotor and the motor housing to the first drive train wherebythe first drive train produces a first output rotation. A second drivetrain connects to another of the rotor and motor housing. A secondtransmission device connects another of the rotor and the motor housingto the second drive train whereby the second drive train produces asecond output rotation. Each of the first and second transmissiondevices comprise a planetary gear. The electric drive also includes atleast one of: the rotor comprising a shaft and a spur gear arranged onthe shaft wherein the spur gear engages with planet wheels of theplanetary gear; and the motor housing is connected to a spur gearwherein the spur gear engages with planet wheels of the planetary gear,and at least one web is connected to axles of the planet wheels of aplanetary gear. The at least one web drives one of the first and thesecond drive train.

The vehicle may comprise a multi-track electric motor vehicle. Theplanet wheels may comprise stepper gears. The rotor may comprise a shaftand a spur gear arranged on the shaft wherein the spur gear engages withidlers of the planetary gear. The idlers may comprise stepper gears. Themotor housing may be connected to a spur gear and wherein the spur gearengages with idlers of the planetary gear. The idlers may comprisestepper gears.

The invention also provides for an electric drive for a vehicle,comprising a main housing. A rotatably mounted motor housing is arrangedin the main housing. A stator and a rotor are arranged in the motorhousing. The rotor and the stator are rotatably mounted within the mainhousing. The motor housing and the rotor are capable of rotating inopposite directions. A first drive train is caused to rotate by therotor. A first transmission device connects the rotor to the first drivetrain whereby the first drive train produces a first output rotation. Asecond drive train is caused to rotate by the motor housing. A secondtransmission device connects the motor housing to the second drive trainwhereby the second drive train produces a second output rotation. Eachof the first and second transmission devices comprise respective firstand second planetary gears. The rotor is coupled to a shaft and a firstspur gear is arranged on the shaft wherein the first spur gear engageswith planet wheels of the first planetary gears. The motor housing iscoupled to a second spur gear wherein the second spur gear engages withplanet wheels of the second planetary gears. A first connectingmechanism connects axles of the first planetary gears to the first drivetrain. A second connecting mechanism connects axles of the secondplanetary gears to the second drive train.

The vehicle may comprise a multi-track electric motor vehicle. Each ofthe first and second planetary gears comprise planet wheels. The planetwheels may comprise stepper gears. The first spur gear may engage withidlers of the first planetary gears. The idlers may comprise steppergears. The second spur gear may engage with idlers of the secondplanetary gears. The idlers may comprise stepper gears. Each of thefirst and second drive trains may be rotatably mounted to the mainhousing via bearings. Each of the rotor and the motor housing may berotatably mounted to the main housing via bearings.

The invention also provides for an electric drive for a vehicle,comprising a main housing. A rotatably mounted motor housing is arrangedin the main housing. A stator is mounted within the motor housing. Arotor is rotatably mounted in the motor housing. The motor housing andthe rotor are capable of rotating in opposite directions. A first drivetrain is caused to rotate by the rotor. A first transmission devicecouples the rotor to the first drive train whereby the first drive trainproduces a first output rotation. A second drive train is caused torotate by the motor housing. A second transmission device couples themotor housing to the second drive train whereby the second drive trainproduces a second output rotation. Each of the first and secondtransmission devices comprise respective first and second planetarygears. A first spur gear is coupled to the rotor wherein the first spurgear engages with planet wheels of the first planetary gears. A secondspur gear is coupled to the motor housing wherein the second spur gearengages with planet wheels of the second planetary gears. The rotationof the rotor causes a rotation of the first drive train and the rotationof the motor housing causes rotation of the second drive train.

The first drive train may be coupled to the planet wheels of the firstplanetary gears. The second drive train may be coupled to the planetwheels of the second planetary gears. The electric drive may furthercomprise a first connecting mechanism that connects axles of the firstplanetary gears to the first drive train and a second connectingmechanism that connects axles of the second planetary gears to thesecond drive train.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the invention is explained in more detail based on theembodiments illustrated in the figures wherein:

FIG. 1 shows a schematic illustration of the drive;

FIG. 2 shows a schematic illustration of the drive, whereby the planetwheels are embodied as stepper gears;

FIG. 3 shows a schematic illustration of the drive in accordance with afurther embodiment;

FIG. 4 shows a cross-section of an electric drive; and

FIG. 5 shows a cross-section of a further embodiment of the electricdrive.

DETAILED DESCRIPTION OF THE INVENTION

By way of introduction, it is noted that in the various embodimentsdescribed the same parts are allocated the same reference numbers andthe same component names, whereby the disclosures contained throughoutthe description can be applied by analogy to the same parts with thesame reference numbers or same component names. Furthermore, positiondetails given in the description, e.g. top, bottom, side, etc., relateto the figure being described and illustrated at the time and with achange of position should be transferred accordingly to the newposition. Moreover, individual features or combinations of features fromthe different embodiments illustrated and described can representindependent inventive solutions or solutions according to the inventionin themselves.

The problem forming the basis of the separate solutions according to theinvention can be taken from the description.

As shown in FIG. 1, the electric drive utilizes a housing 1 that isstationary with reference to the vehicle, from which a first drive train2 and a second drive train 3 protrude on both sides. The torque for thefirst drive train 2 is applied by a stator 4 that is mounted in a motorhousing 5, and the torque for the second drive train 3 is applied by ashaft 6 from a rotor 7 that is mounted on bearings so as to be capableof rotation. The motor housing 5 is fixed to a shaft stump 8 from thefirst drive train 2, whereby the shaft stump 8 has a spur pinion 9 atits free end. Equally, the shaft 6 has a spur pinion 10 at its free end.Between the drive trains 2, 3 and the spur pinions 9, 10, there is agear unit each, embodied as a planetary gear.

Inside the stationary housing 1, within which the whole drive isintegrated, a ring gear 11, 12 is arranged for each of the planetarygears. These ring gears 11, 12 could also be referred to as sun gears,since their axles are in the main axle of the drive. In the gear unitfor drive train 2, the planet wheels 13 are engaged with the ring gear11 and the spur pinion 9. A web 14 is connected to the axles of theplanet wheels 13, which drives the drive train 2 and subsequently therespective wheel shaft.

In order to achieve a reversal of direction for a drive used for avehicle, idlers 15 are arranged in the gear unit for drive train 3,which is also embodied as a planetary gear, and these idlers 15 aremeshed with the spur pinion 10 on the one hand and the planet wheels 16on the other hand, whereby the planet wheels 16 engage with the ringgear 12. The axles of the idlers 15 and the axles of the planet wheels16 are carried by a web 17, which drives the drive train 3 andsubsequently the respective wheel shaft. Of course the planetary gearfor drive train 2 could also have the idlers 15 and the planetary gearfor drive train 3 could have planet wheels 16 that mesh directly withthe ring gear 12 and the spur pinion 10.

FIG. 2 shows a schematic illustration of a gear unit for a drive system,whereby the basic structure of the drive is the same as the drive inaccordance with FIG. 1. In this drive, the planetary gear for drivetrain 2 has planet wheels 13 that are embodied as stepper gears.Equally, the idlers 15 of the corresponding gear unit are embodied asstepper gears. With such a gear embodiment, it is possible to increasethe speed-increase ratio.

FIG. 3 again shows a drive with the same basic configuration as thedrive in FIG. 1. Thereby, the planet wheels 16 for the drive train 3could be embodied as stepper gears, whereby the idlers 15 are of aconventional embodiment. With a suitable choice of tooth ratios for theplanetary gears, the torque in the wheel shafts allocated to the drivetrains can be defined, whereby the rotational movement of the wheelshafts is completely independent.

In accordance with FIG. 4, the electric drive has a fixed housing 1whereby the freely rotating motor housing 5, in which the stator 4 ofthe electric motor is mounted, is supported above the shaft stump 8 byway of roller bearings 18. The shaft stump 8, which is fixed to themotor housing 5, has a spur pinion 9. In the motor housing 5, the rotor7 with its shaft 6 is supported on bearings 19 or 20. The spur pinion 10is provided at one end of the shaft 6. The shaft 6 can also be supportedin the fixed housing 1 by further rolling bearings 21.

Of course the arrangement of the gear units could also be switchedwithout any loss of function.

With the gear arrangement shown in FIG. 5, a further increase in thespeed-increase ratio can be achieved. The basic structure of the driveis equivalent to the drive shown in FIG. 4. The planet wheels 13 andidlers 15 shown in FIG. 4 are embodied as stepper gears 24 and 25 inFIG. 5. Otherwise, the function is exactly the same.

Here, too, it is possible to reverse the gear units.

For form's sake, it is noted that for a better understanding of thestructure of the device, the device and its components are illustratedpartly untrue to scale and/or are enlarged and/or made smaller.

LIST OF REFERENCE NUMBERS

1 Housing 2 Drive train 3 Drive train 4 Stator 5 Motor housing 6 Shaft 7Rotor 8 Shaft stump 9 Spur pinion 10 Spur pinion 11 Ring gear 12 Ringgear 13 Planet wheel 14 Web 15 Idler 16 Planet wheel 17 Web 18 Rollingbearing 19 Bearing 20 Bearing 21 Rolling bearing 22 Field winding 23Slip contact 24 Stepper gear 25 Stepper gear

What is claimed is:
 1. An electric drive for a vehicle, comprising: ahousing that is stationary in relation to a vehicle chassis or frame; amotor housing arranged in the housing; a stator and a rotor arranged inthe motor housing; the rotor and the stator being rotatably mounted; themotor housing and the rotor being capable of rotating in oppositedirections; a first drive train connected to one of the rotor and themotor housing; a first transmission device connecting one of the rotorand the motor housing to the first drive train whereby the first drivetrain produces a first output rotation; a second drive train connectedto another of the rotor and the motor housing; a second transmissiondevice connecting said another of the rotor and the motor housing to thesecond drive train whereby the second drive train produces a secondoutput rotation; each of the first and second transmission devicescomprising planet wheels; at least one of: the rotor comprising a shaftand a spur gear arranged on the shaft wherein the spur gear causesrotation of the planet wheels of either of the first and secondtransmission devices; and the motor housing connected to a spur gearwherein the spur gear engages with the planet wheels of either of thefirst and second transmission devices; a first web directly connected toaxles of the planet wheels of the first transmission device; and asecond web connected to axles of the planet wheels of the secondtransmission device, wherein the first and second webs drive the firstand the second drive trains.
 2. The electric drive of claim 1, whereinthe vehicle comprises a multi-track electric motor vehicle.
 3. Theelectric drive of claim 1, wherein at least some of the planet wheelscomprise stepper gears.
 4. The electric drive of claim 1, wherein therotor comprises the shaft and the spur gear arranged on the shaftwherein the spur gear engages with idlers.
 5. The electric drive ofclaim 4, wherein the idlers comprise stepper gears.
 6. The electricdrive of claim 1, wherein the motor housing is connected to the spurgear and wherein the spur gear engages with idlers.
 7. The electricdrive of claim 6, wherein the idlers comprise stepper gears.
 8. Anelectric drive for a vehicle, comprising: a main housing; a rotatablymounted motor housing arranged in the main housing; a stator and a rotorarranged in the motor housing; the rotor and the stator being rotatablymounted within the main housing; the motor housing and the rotor beingcapable of rotating in opposite directions; a first drive train beingcaused to rotate by the rotor; a first transmission device connectingthe rotor to the first drive train whereby the first drive trainproduces a first output rotation; a second drive train being caused torotate by the motor housing; a second transmission device connecting themotor housing to the second drive train whereby the second drive trainproduces a second output rotation; the first transmission devicecomprising a first planetary gear; the second transmission devicecomprising a second planetary gear; the rotor being coupled to a shaftand a first spur gear being arranged on the shaft wherein the first spurgear causes rotation of planet wheels of the first planetary gear; themotor housing being coupled to a second spur gear wherein the secondspur gear engages with planet wheels of the second planetary gear; afirst connecting mechanism that connects axles of the first planetarygear to the first drive train; and a second connecting mechanism thatconnects axles of the second planetary gear to the second drive train,wherein the planet wheels of both the first and second planetary gearsrotate around an axis running through at least one of: the first andsecond spur gears; and the rotor and the motor housing.
 9. The electricdrive of claim 8, wherein the vehicle comprises a multi-track electricmotor vehicle.
 10. The electric drive of claim 8, wherein at least someof the planet wheels comprise stepper gears.
 11. The electric drive ofclaim 8, wherein the first spur gear engages with idlers of the firstplanetary gear.
 12. The electric drive of claim 11, wherein the idlerscomprise stepper gears.
 13. The electric drive of claim 8, wherein thesecond spur gear engages with idlers of the second planetary gear. 14.The electric drive of claim 13, wherein the idlers comprise steppergears.
 15. The electric drive of claim 8, wherein each of the first andsecond drive trains are rotatably mounted to the main housing viabearings.
 16. The electric drive of claim 8, wherein each of the rotorand the motor housing are rotatably mounted to the main housing viabearings.
 17. An electric drive for a vehicle, comprising: a mainhousing; a rotatably mounted motor housing arranged in the main housing;a stator mounted within the motor housing; a rotor rotatably mounted inthe motor housing; the motor housing and the rotor being capable ofrotating in opposite directions; a first drive train being driven torotate by the rotor; a first transmission device coupling the rotor tothe first drive train whereby the first drive train produces a firstoutput rotation; a second drive train being driven to rotate by themotor housing; a second transmission device coupling the motor housingto the second drive train whereby the second drive train produces asecond output rotation; each of the first and second transmissiondevices comprising respective first and second planetary gears; a firstspur gear being coupled to the rotor wherein the first spur gear engageswith planet wheels of the first planetary gear; and a second spur gearbeing coupled to the motor housing wherein the second spur gear engageswith planet wheels of the second planetary gear, wherein rotation of therotor causes a rotation of the first drive train and wherein rotation ofthe motor housing causes rotation of the second drive train, and whereinthe planet wheels of both the first and second planetary gears rotatearound an axis running through at least one of: the first and secondspur gears; and the rotor and the motor housing.
 18. The electric driveof claim 17, wherein the first drive train is coupled to the planetwheels of the first planetary gear.
 19. The electric drive of claim 17,wherein the second drive train is coupled to the planet wheels of thesecond planetary gear.
 20. An electric drive for a vehicle, comprising:a main housing; a rotatably mounted motor housing arranged in the mainhousing; a stator mounted within the motor housing; a rotor rotatablymounted in the motor housing; the motor housing and the rotor beingcapable of rotating in opposite directions; a first drive train beingdriven to rotate by the motor housing; a first transmission devicecoupling the motor housing to the first drive train whereby the firstdrive train produces a first output rotation; a second drive train beingdriven to rotate by the rotor; a second transmission device coupling therotor to the second drive train whereby the second drive train producesa second output rotation; each of the first and second transmissiondevices comprising respective first and second planetary gears; a firstspur gear being coupled to the motor housing wherein the first spur gearengages with planet wheels of the first planetary gear; a second spurgear being coupled to the rotor wherein the second spur gear causesrotation of planet wheels of the second planetary gear; a firstconnecting mechanism that connects axles of the first planetary gear tothe first drive train; and a second connecting mechanism that connectsaxles of the second planetary gear to the second drive train, whereinrotation of the rotor causes a rotation of the second drive train andwherein rotation of the motor housing causes rotation of the first drivetrain, and wherein the planet wheels of both the first and secondplanetary gears rotate around an axis running through at least one of:the first and second spur gears; and the rotor and the motor housing.21. An electric drive for a vehicle, comprising: a stationary mainhousing; a motor housing arranged in the main housing; a stator and arotor arranged in the motor housing; the rotor being rotatably mountedto the motor housing at two spaced locations arranged on opposite sidesof the stator; the motor housing being rotatably mounted to each of themain housing and the rotor; the motor housing and the rotor beingcapable of rotating in opposite directions; a first drive trainconnected to the motor housing via a first transmission device; a seconddrive train connected to the rotor via a second transmission device;each of the first and second transmission devices comprising planetwheels; a first spur gear rotating with the motor housing and engagingwith the planet wheels of the first transmission device; and a secondspur gear rotating with the rotor and engaging with the planet wheels ofthe second transmission device, wherein and the planet wheels of boththe first and second transmission devices rotate around a common axisrunning through the rotor and the motor housing.
 22. The electric driveof claim 21, wherein axles of the planet wheels of the firsttransmission device are connected to the first drive train and whereinaxles of the planet wheels of the second transmission device areconnected to the second drive train.
 23. The electric drive of claim 21,wherein axles of the planet wheels of the first transmission device areconnected to a web of the first drive train and wherein axles of theplanet wheels of the second transmission device are connected to a webof the second drive train.
 24. A method of driving a vehicle using theelectric drive of claim 1, wherein the method comprises: arranging thehousing in the vehicle in a stationary manner; rotatably mounting thefirst and second drive trains to the housing; and rotating the rotor andthe stator in opposite directions, wherein rotation of the rotor and thestator causes the first and second drive trains to rotate.
 25. A methodof driving a vehicle using the electric drive of claim 8, wherein themethod comprises: arranging the main housing in the vehicle in astationary manner; rotatably mounting the first and second drive trainsto the main housing; and rotating the rotor and the stator in oppositedirections, wherein rotation of the rotor and the stator causes thefirst and second drive trains to rotate.
 26. A method of driving avehicle using the electric drive of claim 17, wherein the methodcomprises: arranging the main housing in the vehicle in a stationarymanner; rotatably mounting the first and second drive trains to the mainhousing; and rotating the rotor and the stator in opposite directions,wherein rotation of the rotor and the stator causes the first and seconddrive trains to rotate.
 27. A method of driving a vehicle using theelectric drive of claim 21, wherein the method comprises: arranging themain housing in the vehicle in a stationary manner; rotatably mountingthe first and second drive trains to the main housing; and rotating therotor and the stator in opposite directions, wherein rotation of therotor and the stator causes the first and second drive trains to rotate.